Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F8/00—Chemical modification by after-treatment
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F16/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal or ketal radical
  • C08F16/02—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal or ketal radical by an alcohol radical
  • C08F16/04—Acyclic compounds
  • C08F16/06—Polyvinyl alcohol ; Vinyl alcohol
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F8/00—Chemical modification by after-treatment
  • C08F8/14—Esterification

Definitions

• the invention relates to a process for the modification of acetalated polyvinyl alcohols by reaction with epoxides.
• Acetalized polyvinyl alcohols e.g. Polyvinyl butyral (PVB) also have increasing viscosities or melt flow indices with increasing molecular weight.
• PVA Polyvinyl butyral
• EP 1 403 289 A1 describes such a method.
• ethylene-vinyl alcohol copolymers are reacted in the extruder with glycidic esters.
• the epoxides are added to the hydroxy functions to give a corresponding side chain.
• the side chain is functionalized by a hydroxy function with different positional isomers.
• the copolymers used here contain between 5 and 55 mol% of ethylene units; the remaining recurring units are vinyl acetate and vinyl alcohol groups.
• the degree of hydrolysis of these polymers is more than 90%, ie the polymers used have a large number of hydroxyl functions.
• the use of polyvinyl alcohols without ethylene units or acetalated polyvinyl alcohols with / without ethylene units, ie compounds with a significantly lower number of free hydroxyl functions is not mentioned in this publication.
• DE 42 019 41 A1 discloses the preparation of a coating system by reacting polyvinyl butyral with glycidyl ethers as epoxide in organic solvents.
• solvents are often not desirable because they are difficult to remove and residues remain in the final product.
• Such polymers are not suitable for example for food packaging.
• the object of the present invention was therefore to provide a process for the preparation of modified, acetalated polyvinyl alcohols which does not have the disadvantages of the prior art.
• the present invention therefore provides a process for the preparation of modified, acetalated polyvinyl alcohols by reacting a melt of the acetalated polyvinyl alcohol with at least one epoxide of the general formula I.
• R 1 H, aliphatic, cycloaliphatic aromatic or aliphatic-aromatic radical having 1 to 20 carbon atoms or CH 2 O (CO) CCH 2
• R 2 and R 2 H, aliphatic radical having 1 to 10 carbon atoms
• the modification of the acetalated polyvinyl alcohols is understood to mean the formal addition of epoxides to its hydroxyl functions.
• the acetalated polyvinyl alcohols used in the process according to the invention preferably have a degree of acetalization of 65-88% by weight.
• these polymers have a proportion of 0.5-8, preferably 1-6 wt.% Restacetat phenomenon and a corresponding proportion of free alcohol functions.
• the acetalated polyvinyl alcohol used is preferably a polyvinyl alcohol acetalated with at least one aliphatic aldehyde having 1 to 10 carbon atoms, in particular polyvinyl butyral.
• the residual polyvinyl alcohol content of the acetalated polyvinyl alcohols used according to the invention is preferably between 10 and 30% by weight, in particular between 14 and 18% by weight or alternatively between 19 and 27% by weight.
• Such polymers are available under the trade name Mowital from Kuraray Specialties Europe GmbH.
• the acetalated polyvinyl alcohols are preferably in the form of a granulate, in particular a granulate prepared by extrusion, for example according to WO 2005/019312 A1 used.
• Granulated products advantageously have a low moisture content and higher solids contents per volume or a higher bulk density.
• the process according to the invention is preferably carried out in the melt of the acetalated polyvinyl alcohol.
• melt temperatures of 150 to 270 ° C, in particular 170 to 250 ° C, or 190 to 250 ° C have proven.
• the reaction is preferably carried out in a tubular reactor, stirred tank or extruder.
• the inventive method is preferably carried out in the presence or under the catalysis of metal salts, such as Zn, Fe and / or Sn salts.
• metal salts such as Zn, Fe and / or Sn salts.
• Particularly suitable is the addition of the catalytic system Zn (acac) 2 / CF 3 SO 3 H / DME according to EP 1 403 289 A1 proved.
• the reaction is preferably carried out in the absence of an organic solvent or water, i. the reaction takes place practically in the polymer melt.
• Small amounts of solvent e.g. required with the addition of the catalyst, do not interfere and are not considered as solvent up to an addition of 5 wt.%.
• the process according to the invention reduces the viscosity of the unmodified starting products with barely changed molar weight, since the reaction preferably takes place without crosslinking of polymer chains.
• the reaction is preferably carried out up to a reduction of the viscosity of the polymers according to the invention of at least 10%, preferably of at least 20%, in particular of at least 30%, based on the acetalated polyvinyl alcohol used.
• the viscosity is determined according to DIN 53015 at 20 ° C using a Höppler viscometer.
• the polymers produced according to the invention can be used as constituents of coating materials such as powder coatings or liquid coatings in the production of Films or in ceramic applications for the production of so-called. Green films are used by the tape-cast process.
• the polymers produced according to the invention furthermore have an improved dispersing behavior and can therefore be used in printing inks, screen printing pastes, metal pigment pastes or for the production of ceramic powders.
• PV acetate content is understood to mean the percentage of acetyl groups resulting from the consumption of the amount necessary for the saponification of 1 g of substance.
• the polyvinyl alcohol content is the percentage of hydroxyl groups that can be detected by the subsequent acetylation with acetic anhydride.
• the acetate group fraction is determined by method a) before and after the reaction.
• the proportion of acetate groups increases by the number of hydroxyl groups reacted with the epoxide.
• the originally present number of hydroxyl groups is determined on the original material according to method b). The difference between these values corresponds to the proportion of vinyl alcohol groups in the polyvinyl acetal reacted with the epoxide.
• the dosage of the polyvinyl acetal is carried out at the feed zone, the metering of the catalyst or the reagent system at heating zone 4.
• the catalyst (Zn (acac) TfO) is previously in situ by the equimolar reaction of 0.1M solution of zinc acetylacetonate (Zn (acac) 2 ) in DME (dimethoxyethane) with 0.1 M solution of trifluoromethanesulfonic acid (TfOH) (in DME). Further details of this catalyst system can be found in EP 1 403 289 A1

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• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
• Pigments, Carbon Blacks, Or Wood Stains (AREA)
• Paints Or Removers (AREA)
• Inks, Pencil-Leads, Or Crayons (AREA)
• Adhesives Or Adhesive Processes (AREA)

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Citations (3)

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• 2005
  • 2005-12-21 EP EP05112546A patent/EP1801132A1/fr not_active Withdrawn
• 2006
  • 2006-12-21 EP EP06841564A patent/EP1991591A1/fr not_active Withdrawn
  • 2006-12-21 WO PCT/EP2006/070106 patent/WO2007071770A1/fr active Application Filing
  • 2006-12-21 US US12/158,101 patent/US8178618B2/en not_active Expired - Fee Related
  • 2006-12-21 CN CN2006800476929A patent/CN101331158B/zh not_active Expired - Fee Related
  • 2006-12-21 KR KR1020087017433A patent/KR20080079683A/ko not_active Application Discontinuation
  • 2006-12-21 JP JP2008546472A patent/JP2009520856A/ja active Pending

Patent Citations (3)

Non-Patent Citations (1)

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